Cell therapy treatment of insulin dependent diabetes is facilitated by the production of unlimited numbers of pancreatic cells that can and will be able to function similarly to human islets. Accordingly, there is a need for producing these pancreatic cell types derived from human embryonic stem (hES) cells, as well as reliable methods for purifying such cells. For example, the use of insulin-producing β-cells derived from human embryonic stem cells (hESCs) would offer a vast improvement over current cell therapy procedures that utilize cells from donor pancreases. Currently cell therapy treatments for diabetes mellitus, such as type 1 or type 2 diabetes, which utilize cells from donor pancreases, are limited by the scarcity of high quality islet cells needed for transplant. For example, cell therapy for a single type 1 diabetic patient requires a transplant of approximately 8×108 pancreatic islet cells (Shapiro et al, 2000, N Engl J Med 343:230-238; Shapiro et al, 2001a, Best Pract Res Clin Endocrinol Metab 15:241-264; Shapiro et al, 2001b, British Medical Journal 322:861). As such, at least two healthy donor organs are required to obtain sufficient islet cells for a successful transplant.
Embryonic stem (ES) cells thus represent a powerful model system for the investigation of mechanisms underlying pluripotent cell biology and differentiation within the early embryo, as well as providing opportunities for genetic manipulation of mammals and resultant commercial, medical and agricultural applications. Furthermore, appropriate proliferation and differentiation of ES cells can potentially be used to generate an unlimited source of cells suited to transplantation for treatment of diseases that result from cell damage or dysfunction. Other pluripotent cells and cell lines including early primitive ectoderm-like (EPL) cells, in vivo or in vitro derived ICM/epiblast, in vivo or in vitro derived primitive ectoderm, primordial germ cells (EG cells), teratocarcinoma cells (EC cells), and pluripotent cells derived by dedifferentiation or by nuclear transfer can also be used.
Accordingly, there is a need for methods for isolation of bona fide pancreatic progenitor cells.